1. Technical Field
Exemplary embodiments of the invention relate to fluid systems. More particularly, exemplary embodiments of the invention relate to a counterbalance adjustment mechanism for adjusting the counterbalancing force applied to a loading arm by a counterbalance mechanism.
2. The Relevant Technology
In many fluid systems, fluids are transferred from one reservoir to another. For instance, in the oil and gas industry, fluids are transferred from storage tanks to transport vehicles (e.g., tank trucks, railroad cars, ships, etc.) so that the fluids may be transported to various destinations. To transfer the fluid from the storage tank to the transport vehicles, the fluids are pumped through a loading arm.
A first end of the loading arm is connected to a riser or stand pipe. The stand pipe is in fluid communication with the storage tank so that the fluid in the storage tank may be pumped from the storage tank and into the loading arm. The stand pipe typically provides a strong platform upon which the loading arm can be mounted.
To facilitate connection of a second end of the loading arm to the transport vehicle, the first end of the loading arm may be connected to the stand pipe with one or more swivel joints. The swivel joints may allow the loading arm to rotate in one or more directions (e.g., about one or more axes of rotation) so that the loading arm may be repositioned to enable the second end of the loading arm to be connected to the transport vehicle.
Due to the weight of the loading arm and the fluids pumped therethrough, mechanisms have been developed to counterbalance the rotational forces resulting from this weight. Counterbalancing the rotational forces reduces the level of effort required of an operator to manipulate the loading arm and increases the safety of these systems. Such counterbalancing mechanisms have included external counterbalancing weights, hydraulic cylinders, spring and lever arm assemblies, pulley and cable systems, and the like. In other cases, internal counterbalancing mechanisms have been used, such as torsion springs disposed with the swivel joints.
For various reasons, such as the fittings used on the loading arm and the weight of the fluids pumped through the loading arm, the counterbalancing force applied to the loading arm by a counterbalance mechanism may need to be adjusted from time to time. Some of the previous counterbalance mechanisms included adjustment mechanisms for adjusting the counterbalancing force. These adjustment mechanisms, however, suffer from a number of limitations. For instance, previous adjustment mechanisms have been difficult to adjust, often requiring the attention of multiple people. Some of the adjustment mechanisms require disassembling the adjustment mechanism from the fluid system so the adjustment mechanism can be taken to a shop to be adjusted. Still further, previous adjustment mechanisms have been difficult to precisely adjust. Moreover, adjusting some of the previous adjustment mechanisms can pose a safety risk to the personnel performing the adjustment.
Accordingly, what is desired is an adjustment mechanism that can simply, easily, and safely adjust the counterbalancing force applied to a loading arm and any fluid therein.